KR20090042576A - Arc detection apparatus and arc monitoring method - Google Patents

Abstract

An arc detecting apparatus and an arc sensing method is provided to monitor the abnormality of the plasma process by determining the generation of arc. An arc detecting apparatus comprises a sensor and a processing unit. The sensor measures the electric signal of the current or voltage of the transmission line. The processing unit processes the voltage signal or the current signal(SV',SI') which is the output signal of sensor and determines the generation of arc. The processing unit processes the voltage signal or the current signal, and produces the envelope signal, and determines the generation of arc by using the envelope signal corresponding to arc in the load. The processing unit comprises a pre-processing unit(25) and a determining unit(10). The pre-processing unit processes the voltage signal or the current signal, and produces the ARC detection signal(OUT), the voltage envelope signal, and the current envelope signal(Vrms,Irms). The determining unit determines the generation of arc by using width and/or the slope of the current envelope signal and/or the voltage envelope signal.

Description

Arc detection device and arc detection method {ARC DETECTION APPARATUS AND ARC MONITORING METHOD}

The present invention relates to an arc detection device of a discharge device for generating a plasma, and more particularly, to an arc detection device and an arc detection method of a plasma generation device for discharging by using a radio frequency (RF) power source.

Plasma processing apparatuses are widely used in semiconductor manufacturing processes, liquid crystal display (LCD) manufacturing processes, solar cell manufacturing processes, material surface treatment, air pollution treatment, fusion fusion, and the like. In particular, a plasma processing apparatus used in a semiconductor manufacturing process mainly uses an RF power source to generate a plasma.

On the other hand, in the plasma processing process using the RF power source, if there are structural defects or small particles in the discharge vessel, an arc may be generated to reduce the stability of the plasma processing process. In particular, in the case of a plasma processing apparatus for the manufacture of semiconductor devices, the arc can generate other small particles that cause the failure of the semiconductor devices.

Accordingly, in order to monitor the stability of the plasma treatment process, a technique for monitoring the occurrence of an arc inside the chamber is required. According to the prior art, the generation of the arc has been monitored through analysis of the optical properties of the plasma. However, these optical monitoring methods have technical limitations that make it difficult to determine the type of arc. More specifically, arcs generated in the chamber may be classified into soft arcs with little current change and hard arcs with much current change. The optical monitoring method is difficult to provide information about this type of arc. In addition, for this optical monitoring, the side wall of the chamber should be provided with a window allowing observation of plasma emission, and the contamination of the window, which degrades the reliability of the optical signal, increases as the processing time increases. It also increases.

Although a method of arranging a sensing device for monitoring arc generation inside the chamber can be considered, this method not only requires modification of the chamber structure but can also degrade the quality of the generated plasma.

One technical problem of the present invention is to provide an arc sensing device that enables to monitor in real time the presence of abnormality of the arc generation and the plasma treatment process, and to monitor the occurrence of the arc generation and the abnormality of the plasma treatment process without changing the chamber structure. There is.

One technical problem of the present invention is to provide an arc detection method capable of monitoring the occurrence of abnormality of the arc generation and the plasma treatment process in real time, and to monitor the presence of abnormality of the arc generation and the plasma treatment process without changing the chamber structure.

 In the arc sensing device according to the present invention, in the RF discharge power supply power to the load through the transmission line, the sensing unit for measuring the electrical signal of the current or voltage of the transmission line, and the voltage signal or current that is the output signal of the sensing unit And a processor configured to process the signal to determine arc generation, wherein the processor generates the envelope signal by processing the voltage signal or the current signal, and determines whether the arc is generated using the envelope signal corresponding to the arc generation at the load. do.

In one embodiment of the present invention, the processor is a pre-processing unit for generating a soft arc detection signal and / or the envelope signal by processing the voltage signal, and determining the soft arc generation using the slope of the envelope signal Including a portion, wherein the envelope signal is a voltage envelope signal processing the voltage signal.

In one embodiment of the present invention, the processing unit converts the offset signal into an analog signal to generate an analog offset signal and transmits to the pre-processing unit, the digital analog converter to convert the envelope signal of the pre-processing unit into a digital signal The control unit further comprises at least one of an analog-digital converter provided to a determination unit, a control unit for controlling the determination unit, and an interface for communicating with the determination unit or the controller and an external power source, a host, an input / output device, an HMI, and the offset signal. May be provided by any one of the host, the controller, and the determination unit.

In one embodiment of the present invention, the preprocessing unit is an envelope generator for processing the voltage signal to generate the voltage envelope signal, a first soft arc detector for generating a first soft arc detection signal, and a second soft arc detection It may include a second soft arc detector for generating a signal.

In one embodiment of the present invention, the first soft arc detector compares the first comparison signal and the first reference signal to generate the first soft arc detection signal, the information on the arc by processing the voltage envelope signal A first reference signal generator for generating the first reference signal from which the first reference signal is removed, a first comparison signal generator for generating a first comparison signal including information on an arc by processing the voltage envelope signal, and the first reference signal And a first comparator for comparing the first comparison signal with the first comparison signal to generate the first soft arc detection signal.

In one embodiment of the present invention, the second soft arc detector compares the second comparison signal and the second reference signal to generate the second soft arc detection signal, the information on the arc by processing the voltage envelope signal A second reference signal generator for generating the second reference signal from which the second reference signal is removed, a second comparison signal generator for generating the second comparison signal including information on the arc by processing the voltage envelope signal, and the second reference signal And a second comparator comparing the second comparison signal with the second comparison signal to generate the second soft arc detection signal.

In one embodiment of the present invention, the determination unit may include a soft arc generation determiner for outputting a soft arc generation signal using the slope of the envelope signal corresponding to the arc generation in the load.

In one embodiment of the present invention, the determination unit may further include a soft arc counter for calculating the number of the soft arc generation signal.

In one embodiment of the present invention, the processing unit includes an analog-to-digital converter for converting the envelope signal of the pre-processing unit to a digital signal to output a digital envelope signal, the determination unit inputs the soft arc generation signal as an operation signal A memory for storing the digital envelope signal of the analog-to-digital converter, and the soft arc generation signal as an operation signal to determine whether the streamer is changed by using the change of the digital envelope signal and / or the duration of the change. And a streamer determiner for outputting an interlock signal.

In one embodiment of the present invention, while controlling the power using the interlock signal, the interlock signal may be transmitted to the power through an interface.

In one embodiment of the present invention, the processing unit includes a preliminary processing unit for processing the current signal to generate a hard arc detection signal and / or the envelope signal, and a determination unit for processing the hard arc detection signal, the envelope The signal is a current envelope signal obtained by processing the current signal.

In one embodiment of the present invention, the preprocessor may include a current envelope generator for processing the current signal to generate a current envelope signal, and a hard arc detector for generating a hard arc detection signal.

The hard arc detector may generate the hard arc detection signal by comparing a third comparison signal with a third reference signal, and process the current envelope signal to remove information on the arc. A third reference signal generator for generating a third reference signal, a third comparison signal generator for processing the current envelope signal to generate a third comparison signal including information on an arc, and the third reference signal and the third Comparing the comparison signal, it may include a third comparator for generating the hard arc detection signal.

In one embodiment of the present invention, the determination unit may further include a hard arc counter for calculating the number of the hard arc detection signal.

In one embodiment of the present invention, the processing unit is a pre-processing unit for generating a soft arc detection signal and / or the envelope signal by processing the voltage signal or current signal, and soft arc generation using the width of the envelope signal The determination unit may include a determining unit.

In the arc detection method of the present invention, in the RF discharge power supply power to the load through the transmission line, detecting the electrical signal of the current or voltage of the transmission line to generate a current signal and a voltage signal, the voltage signal and the And a preprocessing step of generating an arc detection signal and an envelope signal by processing the current signal, and determining an arc generation using the slope or width of the envelope signal.

In an exemplary embodiment, the preliminary processing may include generating an envelope signal by processing the current signal and the voltage signal, and generating an arc detection signal using the envelope signal.

In one embodiment of the present invention, generating the arc detection signal

Generating a comparison signal including information about an arc by using the envelope signal, generating a reference signal except information about an arc by using the envelope signal, and comparing the comparison signal with the reference signal to generate an arc Forming a detection signal.

In an embodiment of the present disclosure, the determining of the arc generation comprises: processing the arc detection signal to generate an arc generation signal by determining an arc generation using a slope of the envelope signal or a width of the envelope signal. At least one of: counting the arc generation signal, generating an interlock signal using a change and a duration of the arc generation signal and the envelope signal, and controlling a power source using the interlock signal It may include.

The present invention detects electrical signals of current and voltage of a transmission line to generate current and voltage signals. The voltage signal and the current signal are processed to generate an envelope signal. The occurrence of the arc is determined using the slope of the envelope signal corresponding to the arc generation. As a result, it is possible to distinguish between arc, plasma characteristic change and noise, and to be easily installed in the discharge system, and real-time monitoring is possible. Therefore, it is possible to determine whether there is an abnormality in the plasma treatment step at an early stage.

An arc may be divided into a hard arc and a soft arc. When the hard arc occurs, the electrical characteristics of the overall plasma of the RF discharge may change significantly. This is because high density ionization can occur between the electrode in the discharge vessel and the ground. Therefore, when the hard arc occurs, the RF discharge may become unstable as a whole or the RF discharge may not be maintained. When the incident power to the load is constant, when the hard arc occurs, the current of the transmission line may increase rapidly, and the voltage of the transmission line may decrease. Alternatively, when the hard arc occurs, the current of the transmission line increases, and the voltage of the transmission line may not change.

The duration of the hard arc inside the plasma may be several nsec to several usec, but the duration of disturbance of the current or voltage of the transmission line may be further extended. The electrical signal of the transmission line according to the hard arc generation is perturbated from the steady state electrical signal. The disturbance component caused by the hard arc may include several hundred KHz in the frequency space.

When a soft arc occurs, both the current and voltage of the transmission line can be reduced, and the RF discharge can be maintained well. The soft arc may appear as an early phenomenon of the hard arc. When the soft arc is generated, the duration of disturbance of the current and the voltage of the transmission line may be about several usec. The electrical signal of the transmission line according to the soft arc generation may be perturbated from the steady state electrical signal. The disturbance component due to the soft arc may be in the 1 MHz region in the frequency space.

When the soft arc occurs, the soft arc may last for several tens of msec or more. Let's call this lasting soft arc a streamer. If the streamer occurs, it is necessary to immediately remove the power from the load. When the streamer is generated, the current may hardly change.

When an arc occurs, the electrical characteristics of the transmission line change drastically. Therefore, the investigation of the electrical characteristics of the transmission line may be the most reliable means for determining whether the arc occurs. In addition, the electrical characteristics of the transmission line can be monitored in real time.

Electrical characteristics of the transmission line may be affected by arc generation and plasma characteristic change. Therefore, it is necessary to distinguish between the plasma characteristic change and the arc. The duration of the plasma characteristic change is about several hundred msec in time, and the duration of the arc may last for several usec to several hundred usec.

On the other hand, in the case of turning on the RF power and turn off the RF power, if it is determined whether the arc generation through the duration of the disturbance of the current and voltage of the transmission line corresponding to the arc generation of the load, You can make wrong decisions. Comparing the case of turning on the RF power with the case of turning off the RF power and in the case of arc discharge, it can be seen that the slope of the envelope of the voltage or current of the transmission line is different.

Thus, in order to determine whether an arc has occurred, it is necessary to compare the slope of the envelope of the electrical signal corresponding to the arc generation of the load and / or the duration (or width) of the envelope. In addition, the change tendency of the electrical signals of the current and voltage may also affect the arc judgment.

The above objects, other objects, features and advantages of the present invention will be readily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments described are provided so that the disclosure may be thorough and complete, and the spirit of the present invention will be fully conveyed to those skilled in the art. Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments of the present invention.

1 is a block diagram showing a schematic configuration of an arc detection apparatus according to an embodiment of the present invention.

Referring to FIG. 1, an arc sensing apparatus according to the present invention includes a sensing unit 22 measuring electrical signals SV and SI of current or voltage of a transmission line, and a voltage signal or an output signal of the sensing unit 22. And a processor 26 for processing the current signals SV 'and SI' to determine arc generation.

The arc sensing device includes a load 24, an RF power source 3 for supplying power to the load 24, a transmission line 36 disposed between the load 24 and the RF power source 3, and a matching network ( 38) may be further included.

The detection unit 22 is disposed around the transmission line 36 to measure electrical signals SV and SI of the current or voltage of the transmission line 36, and the detection unit 22 includes the voltage signal or current signal. It is electrically connected to a processing unit 25 for processing (SV ', SI').

The RF power supply 3 supplies incident power to the input terminals N1 and N2. Part of the incident power supplied through the transmission line 36 is consumed by the load 24, and the other part is reflected from the load 24 to the input terminals N1 and N2. Accordingly, the matching network 38 may be configured to transmit the incident power to the load 24, and may be disposed between the input terminals N1 and N2 and the load terminals N3 and N4. The driving frequency of the RF power source 3 may be one of 200 KHz to 500 MHz. According to an embodiment of the present invention, the driving frequency may be 13.56 MHz.

According to a modified embodiment of the present invention, the RF power source 3 may consist of one or more power sources. For example, when the RF power source 3 is configured of a first power source and a second power source, driving frequencies of the first power source and the second power source may be different from each other. In addition, the first power source and the second power source may be connected to the same load. In this case, a first matching network and a first sensing unit may be disposed between the first power source and the load, and a second matching network and a second sensing unit may be disposed between the second power source and the load. Alternatively, after the first matching network and the second matching network are combined into one, one sensing unit 22 may be disposed in front of the load.

The internal impedance of the RF power supply 3 may be 50 ohms, and the characteristic impedance of the transmission line 36 may be 50 ohms. The transmission line 36 may include at least one of a coaxial cable, two wires, a strip line, and a bus bar.

The load 24 is connected to the load terminals N3 and N4 and may be an electrode or an antenna for generating plasma. The impedance of the load 24 may change with time due to a change in plasma characteristics or arc generation. In this case, the reactances of the variable reactance elements 12 and 14 of the matching network 38 may be changed to maximize the aforementioned incident power.

The detector 22 is arranged to measure an electrical signal SV or SI of a voltage or a current of the transmission line 36 connecting the input terminals N1 and N2 and the load terminals N3 and N4. The detector 22 may be disposed between the load terminals N3 and N4 and the matching network 38, or between the input terminals N1 and N2 and the matching network 38. In addition, the detector 22 may be located inside the matching network 38.

The sensing unit 22 includes at least one sensor disposed around the transmission line 36, wherein the sensor measures a current flowing through the transmission line and outputs a current signal SI ′ of the current measuring line and the transmission line. It may include at least one of the voltage meter for measuring the voltage to output the voltage signal (SV '). The current meter may include a coil 18 for measuring induced electromotive force. For example, the current meter may be a Rogowski coil measuring an electromotive force. The voltage meter may be a voltage divider 20 using an electrode or a resistor.

The processor 26 processes the voltage signals or the current signals SV ′ and SI ′ of the detector 22 to determine whether an arc is generated. The processor 25 processes the voltage signal or the current signals SV ′ and SI ′ to generate voltage envelope signals and current envelope signals Vrms and Irms, and corresponds to arc generation at the load 24. The occurrence of an arc is determined using the voltage envelope signal and the current envelope signals Vrms and Irms.

The processor 26 may determine whether an arc is generated by using slopes of the voltage envelope signal and / or current envelope signals Vrms and Irms corresponding to arc generation in a load. According to a modified embodiment of the present invention, it is possible to determine whether an arc is generated using the duration (width) of the voltage envelope signal and the current envelope signals Vrms and Irms corresponding to the arc generation in the load. Specifically, whether or not a soft arc is generated may be determined using the slope of the voltage envelope signal Vrms, and the hard arc may be determined using the width of the current envelope signal Irms.

FIG. 2 is a block diagram showing a schematic configuration of the processing unit 25 described with reference to FIG. 1.

The processor 26 receives the voltage signals or the current signals SV ′ and SI ′ of the detector 22 and outputs the arc detection signal OUT and / or the voltage envelope signal and the current envelope signals Vrms and Irms. The preprocessing unit 25 may include a determination unit 10 that determines whether an arc is generated using the arc detection signal OUT of the preprocessing unit 25. The preliminary processing unit 25 may be configured by a circuit that processes an analog signal, and the determination unit 10 may be configured by a circuit that processes a digital signal. According to a modified embodiment of the present invention, the preliminary processing unit 25 converts the current signal SI 'and the voltage signal SV' of the sensing unit 22 into digital signals and converts them into digital signals. It can be configured by.

In addition, the processor 26 controls the determination unit 10 and the offset signals DOS1, DOS2, and DOS3 set by the determination unit 10 to the analog offset signals OS1, OS2, and OS3. At least one of the digital analog converter (7, DAC) is converted into a) and transmitted to the preliminary processing unit 25. The processor 26 converts the voltage envelope signal and the current envelope signals Vrms and Irms generated by the preprocessor 25 into digital signals and transmits them to the determination unit 10. And at least one of interfaces 8 and IF communicating with the determination unit 10 and an external power source 3, a host 6, an input / output device 4, a human machine interface (HMI), and the like. Can be. The offset signals DOS1, DOS2, and DOS3 may be provided to the determination unit 10 via the interface 8 and the control unit 34 with values set by the host 6. The interface 8 transmits the interlock signal INT_LCK of the determination unit 10 to the power source 3. The power source 3 may then be turned off by the interlock signal INT_LCK.

 The hard arc count signal H_CNT, the soft arc count signal S_CNT, and / or the total arc count signal ARC_CNT of the determination unit 10 are connected to the input / output device 4 and / or through the interface 8. Or to the host 6. The input / output device 4 may display the hard arc count signal H_CNT, the soft arc count signal S_CNT, and / or the total arc count signal ARC_CNT on the display device. The host 6 may control the power source 3 using the hard arc count signal H_CNT, the soft arc count signal S_CNT, and / or the total arc count signals ARC_CNT. Variables necessary for the determination unit 10 may be set by the host 6 and provided to the determination unit 10 through the interface 8 and the control unit 34.

3 is a block diagram illustrating a schematic configuration of a preliminary processing unit and a determination unit according to an embodiment of the present invention.

Referring to FIG. 3, the processor 26 processes a voltage signal or a current signal SV ′ and SI ′ to generate an arc detection signal OUT and the voltage envelope signal and the current envelope signal Vrms and Irms. The processor 25 and the determination unit 10 that determines the occurrence of the arc by using the slope and / or the width of the voltage envelope signal and / or the current envelope signal (Vrms, Irms).

The preliminary processing unit 25 processes the voltage envelope generator 50a to process the voltage signal SV ′ and generates the voltage envelope signal Vrms, and the current signal SI ′ to process the current envelope signal Irms. ) May include a current envelope generator 50b. The voltage envelope generator or the current envelope generators 52a and 52b may remove driving frequency components of a power supply from the voltage signal or the current signals SV ′ and SI ′, respectively, and output an average square root value or a maximum value. The envelope generators 52a and 52b may include at least one of a half wave rectifier, a full wave rectifier, an RMS detector, or a peak detector. In addition, the envelope generators 52a and 52b may convert the mean square root value or the maximum value of the voltage signal or the current signal SV 'and SI' into a log value and output the log value. The output signal of the envelope generators 52a and 52b may include information on arc generation.

In addition, the preliminary processing unit 25 processes the voltage envelope signal Vrms and the first analog offset signal OS1 to output a first soft arc detection signal OUT1, and the first soft arc detector 52a. A second soft arc detector 52b for processing a voltage envelope signal Vrms and the second analog offset signal OS2 to output a second soft arc detection signal OUT2, and the current envelope signal Irms and the first soft arc detector 52b. At least one of the hard arc detector 52c for processing the three analog offset signal OS3 and outputting the hard arc detection signal OUT3 may be further included.

The slope of the voltage envelope signal Vrms corresponding to arc generation may be obtained by differentiating the voltage envelope signal Vrms. For example, the derivative compares the voltage envelope signal corresponding to the arc generation with two reference signals constant over time, and measures a time difference between intersections of the voltage envelope signal Vrms and the two reference signals. Can be performed. The reference signal may be set by a ratio of the voltage envelope signal corresponding to a steady state. The percentage may be between 70 percent and 5 percent. Accordingly, the slope of the voltage envelope signal Vrms corresponding to arc generation can be calculated. The ratio may be set in the determination unit 10.

 According to a modified embodiment of the present invention, the method for obtaining the slope of the envelope signal corresponding to arc generation may be variously modified.

The determination unit 10 may include a soft arc generation determiner 60 and a soft arc counter 62. The soft arc generation determiner 60 receives the first and second soft arc detection signals OUT1 and OUT2 and the reference slope signal T_slope and outputs the arc generation signal S1. The soft arc generation determiner 60 calculates a difference between the occurrence points of the first soft arc detection signal OUT1 and the second soft arc detection signal OUT2 to calculate the slope of the voltage envelope signal Vrms. do. In addition, the soft arc generation determiner 60 receives a reference slope signal T_slope, and the difference between the occurrence time point of the first soft arc detection signal and the second soft arc detection signal and the reference slope signal T_slope. Comparing with and outputs the soft arc generating signal (S1) when the reference slope signal (T_slope) is in the range. The reference slope signal T_slope may be transmitted to the determination unit 10 through a value set by the host 6 through the interface 8 and the control unit 34.

According to a modified embodiment of the present invention, the soft arc generation determiner 60 may determine whether the arc is generated using the slope and / or width of the voltage envelope signal Vrms corresponding to the arc generation. Specifically, when the slope of the voltage envelope signal Vrms is within a predetermined range and the width of the voltage envelope signal Vrms is within a predetermined range, the soft arc generation determiner 60 includes the voltage envelope signal. (Vrms) can be judged as soft arc generation.

The soft arc counter 62 receives the sort arc generation signal S1, calculates the number, and outputs the soft arc count signal S_CNT. The host 6 may receive the soft arc count signal S_CNT through the interface 8 to control the power source 3. The input / output device 4 may receive the soft arc count signal S_CNT through the interface 8 and display it on the display device.

The determination unit 10 includes a memory 66 and a streamer determination unit 68. The memory 66 may receive the soft arc generation signal S1 as an operation signal and store the digital voltage envelope signal and the digital current envelope signals Vrms and DIrms of the analog-to-digital converter 5. The streamer determiner 68 receives the soft arc generation signal S1 as an operation signal, and determines whether the streamer is changed by using the change of the envelope signals Vrms and Irms and the duration of the change. The lock signal INT_LCK can be output. The interlock signal INT_LCK is transmitted to the power source 3 via an interface 8. The power source 3 may be controlled by the interlock signal INT_CLK.

The memory 66 stores the digital voltage envelope signal and the digital current of the analog-to-digital converter 5 for a predetermined time before and after the generation of the soft arc generation signal S1 based on the soft arc generation signal S1. Envelope signals (DVrms, DIrms) can be stored. The digital voltage envelope signal and the digital current envelope signals DVrms and DIrms of the analog-to-digital converter 5 contain information on arc generation. In the streamer generation, the digital current envelope signal DIrms may decrease or hardly change by several tens of percent or less in the steady state signal. Meanwhile, the digital voltage envelope signal DVrms decreases rapidly in response to arc generation. That is, the difference between the conventional soft arc and the streamer may be a change in the tendency of the digital current envelope signal (DIrms). By detecting the difference and the duration Tstm (hereinafter, streamer duration) of the digital voltage envelope signal DVrms, the streamer determiner 68 may determine whether the streamer is a normal soft arc or not. have. The streamer duration Tstm may be several hundred usec to several tens of msec. The streamer duration Tstm may be a value set in the host 6 through the interface 8 and the control unit 34.

The preliminary processing unit 25 includes a current envelope generator 50b and a hard arc detector 52c. The current envelope generator 50b receives the current signal SI 'and generates a current envelope signal Irms. The hard arc detector 52c receives the current envelope preference Irs and the third analog offset signal OS3 to generate the hard arc detection signal OUT3. The configuration of the hard arc detector 52c is substantially the same as the first soft arc detector 52a. The hard arc detection signal OUT3 may be proportional to the duration of the arc.

The determination unit 10 may further include a hard arc counter 64 that calculates the number of the hard arc detection signals OUT3. In the event of a hard arc, the current envelope signal Irms increases above its normal state. The hard arc detector 52c may detect this characteristic and output the hard arc detection signal OUT3.

According to a modified embodiment of the present invention, the determination unit 10 may further include a hard arc generation determiner (not shown) that determines the occurrence of a hard arc by measuring the width of the hard arc detection signal. If the width of the hard arc detection signal OUT3 is several tens of nsec to several usec, the hard arc generation determiner may determine the hard arc detection signal OUT3 as a hard arc. According to a modified embodiment of the present invention, the hard arc generation determiner may determine whether a hard arc occurs using the width of the current envelope signal (Irms) and / or the slope of the current envelope signal (Irms).

 The determination unit 10 outputs the total arc count signal ARC_CNT by adding the soft arc count signal S_CNT of the soft arc counter 62 and the hard arc count signal H_CNT of the hard arc counter 64. A summer 70 is further included. The input / output device 4 and the host 6 receive the hard count signal H_CNT and / or the total arc count signal ARC_CNT through the interface 8 to display the display device on the display device, or The power supply 3 can be controlled.

Figure 4 is a block diagram showing the configuration of an arc detector according to an embodiment of the present invention.

The arc detectors 52a, 52b, and 52c may measure the slope and / or the width of the voltage envelope signal and / or the current envelope signals Vrms and Irms. The slope of the voltage envelope signal Vrms may be obtained by using a difference between a generation time (time of occurrence) of the first soft arc detection signal OUT1 and the second soft arc detection signal OUT2.

In detail, the first soft arc detector 50a includes a first comparison signal generator 90a, a first reference signal generator 93a, and a first comparator 96a. The first comparison signal generator 90a receives the voltage envelope signal Vrms and outputs a first comparison signal IN1 including information about an arc but removing noise. The first comparison signal generator 90a may include a first comparison signal filter to remove noise of a high frequency component from the voltage envelope signal Vrms. The first comparison signal filter may be configured to extract a component of a disturbing frequency band by an arc from an input signal. The disturbing frequency band may be 10 KHz to 250 KHz. Accordingly, the first comparison signal filter may be a low pass filter or a band pass filter. The first comparison signal filter may be an active filter or a passive filter.

The first reference signal generator 93a may include a combiner 92a and a first reference signal filter 94a. The combiner 92a may receive the first analog offset signal OS1 and the voltage envelope signal Vrms of the digital analog converter 7 and sum them. Accordingly, the voltage envelope signal Vrms may have an offset or a DC bias. The first reference signal filter 94a receives the output signal of the combiner 92a, removes information on arc generation, and outputs a first reference signal REF1. The first reference signal filter 94a may be a low pass filter, and the cutoff frequency may be 10 KHz. As a result, the frequency band filtered by the first comparison signal filter 90a is different from the frequency band filtered by the first reference signal filter 94a. According to an embodiment to be modified, the positions of the combiner 92a and the first reference signal filter 94a may be interchanged. The first comparator 96a receives the first comparison signal IN1, which is an output signal of the first comparison signal generator 90a, and the first reference signal REF1, which is an output signal of the first reference signal generator 93a. In comparison, the first soft arc detection signal OUT1 is generated.

The second soft arc detector 52b may include a second reference signal generator 93b, a second comparison signal generator 90b, and a second comparator 96b. The second comparison signal generator 90b receives the voltage envelope signal Vrms and outputs a second comparison signal IN2 including information about the arc but removing noise. The second reference signal generator 93b includes a combiner 92b and a second reference signal filter 94a. The combiner 92b receives the voltage envelope signal Vrms and the second analog offset signal, and adds the received signal. The second reference signal filter 94b receives the output signal of the combiner 92b and removes information on the arc to output the second reference signal REF2. The second comparator 96b compares the second comparison signal IN2 and the second reference signal REF2 so that the second arc when the second reference signal REF2 is greater than the second comparison signal IN2. The detection signal OUT2 is output high. The second soft arc detector 52b may have a configuration substantially the same as that of the first soft arc detector 52a. Meanwhile, the first analog offset signal OS1 and the second analog offset signal OS2 may be different from each other and may be negative. The first comparison signal IN1 and the second comparison signal IN2 may have the same value.

The hard arc detector 52c may include a third reference signal generator 93c, a third comparison signal generator 90c, and a third comparator 96c. The third comparison signal generator 90c includes the arc information in the current envelope signal Irms, and removes noise to output a third comparison signal. The third reference signal generator 93c may include a combiner 92c and a third reference signal filter 94c. The combiner 92c receives the current envelope signal Irms and the third analog offset signal OS3 and sums these signals and outputs them. The third reference signal filter 94c receives the output signal of the combiner 92c and removes information on the arc to output the third reference signal REF3. The third comparator 96c compares the third reference signal REF3 with the third comparison signal IN3 to generate the hard arc detection signal OUT3. The hard arc detector 52c may have a configuration substantially the same as that of the first soft arc detector 52a. The third analog offset signal OS3 may be a positive value. Accordingly, when the current envelope signal Vrms corresponding to the arc generation rises above the normal state, it may be determined as a hard arc.

 According to a modified embodiment of the present invention, the first reference signal generator 93a may include a reference signal filter (not shown) and a differentiator (not shown). The reference signal filter may receive the voltage envelope signal Vrms of the envelope generator 50a to remove information about the arc. The differentiator may receive an output signal of the reference signal filter and a first analog offset signal OS1 and output a difference between these signals.

FIG. 5 shows the voltage signal SV ′, the first and second comparison signals IN1 and IN2, the first and second reference signals REF1 and REF2, and the first soft signal in the soft arc detector according to an exemplary embodiment of the present invention. Graphs illustrating the arc detection signal OUT1 and the second soft arc detection signal OUT2. However, the x-axis represents time and the y-axis represents voltage (V).

Referring to FIG. 5, the voltage signal SV ′ varies in response to arc generation A, B, C, and D. The voltage signal SV 'has a maximum value of V1 in a steady state. The maximum value of the voltage signal SV 'may change to V2 due to the change in the load. The change in steady state may be due to a change in plasma characteristics.

The DC bias of the first reference signal REF1 and the second reference signal REF2 may have a different value. The DC bias can be selected at a constant rate from a steady state value. The first soft arc detection signal OUT1 compares the first reference signal REF1 with the first comparison signal IN1, so that the first reference signal REF1 is greater than the first comparison signal IN1. Larger may be high. The second soft arc detection signal OUT2 compares the second reference signal REF2 with the second comparison signal IN2, so that the second reference signal REF2 is greater than the second comparison signal IN2. If large, it may be high.

6 illustrates a first comparison signal IN1, first and second reference signals REF1 and REF2, a first soft arc detection signal OUT1, and a second soft arc detection according to the arc generation A of FIG. 5. Graphs showing the signal OUT2.

5 and 6, the first soft arc detection signal OUT1 is generated by comparing the first comparison signal IN1 and the first reference signal REF1. In addition, the second soft arc detection signal OUT2 is generated by comparing the second comparison signal IN2 and the second reference signal REF2. However, the first comparison signal IN1 and the second comparison signal IN2 may be the same. The width of the first soft arc detection signal OUT1 is T1. The width of the second soft arc detection signal OUT2 is T2. The difference between the generation time (time of occurrence) of the first soft arc detection signal OUT1 and the generation time (or time of occurrence) of the second soft arc detection signal OUT2 is the voltage envelope signal Vrms corresponding to arc generation. Is proportional to the slope of. The difference T3 between the generation time (time of occurrence) of the first soft arc detection signal OUT1 and the generation time (or time of occurrence) of the second soft arc detection signal OUT2 is compared with the reference slope signal T_slope. . The reference slope signal T_slope may be several tens of nsec to several usec. The difference T3 between the generation time (time of occurrence) of the first soft arc detection signal OUT1 and the generation time (or time of occurrence) of the second soft arc detection signal OUT2 is in the range of the reference slope signal T_slope. If inside, the first and second soft arc detection signals OUT1 and OUT2 are determined to be soft arc generation. That is, when the difference T3 between the generation time (time of occurrence) of the first soft arc detection signal OUT1 and the generation time (or time of occurrence) of the second soft arc detection signal OUT2 is several tens of nsec or less, The first and second soft arc detection signals OUT1 and OUT2 may be caused by noise. In addition, when the difference T3 between the generation time (time of occurrence) of the first soft arc detection signal OUT1 and the generation time (or time of occurrence) of the second soft arc detection signal OUT2 is several or more usec, The first and second soft arc detection signals OUT1 and OUT2 may occur due to changes in plasma characteristics.

According to a modified embodiment of the present invention, the width T1 of the first soft arc detection signal OUT1, the width T2 of the second soft arc detection signal OUT2, and the first and second soft arcs. The energy of the arc can be calculated using the difference in time T3 of the detection signals OUT1 and OUT2.

7 is a diagram illustrating first and second comparison signals IN1 and IN2, third comparison signal IN3, first and second reference signals REF1 and REF2, and a third reference in a processor according to an exemplary embodiment of the present invention. The signal REF3, the first and second soft arc detection signals OUT1 and OUT2, the hard arc detection signal OUT3, the soft arc generation signal S1, the total arc count signal ARC_CNT, and the interlock signal INT_LCK. It is a graph. The x-axis is time and the y-axis is voltage.

The first and second comparison signals IN1 and IN2 have a characteristic of rising and decreasing at an initial time of turning on power. The initial variation of the first and second comparison signals IN1 and IN2 has a slope distinct from the arc. According to a modified embodiment of the present invention, when the power is increased, the arc detecting apparatus may have a delay time DELAY_TIME which does not detect an arc for a predetermined time.

The first and second comparison signals IN1 and IN2 with respect to the voltage may change corresponding to the soft arc generations a, c, and d, and may be reduced from the normal state. In the steady state, the first and second reference signals REF1 and REF2 smaller than the first and second comparison signals IN1 and IN2 have information on arc generation despite the soft arc generation a, c, and d. Does not include Accordingly, the first soft arc detection signal OUT1 and the second soft arc detection signal OUT2 are generated in response to the soft arc generations a, c, and d. The first soft arc detection signal OUT1 is high when the first reference signal REF1 is greater than the first comparison signal IN1. In addition, the second soft arc detection signal OUT2 is high when the second reference signal REF2 is greater than the second comparison signal IN2.

The third comparison signal IN3 related to the current increases and decreases at an initial time when the power is turned on. In the steady state, the third comparison signal IN3 related to the current may change to correspond to the hard arc generation b and may increase from the steady state. The third reference signal REF3 larger than the third comparison signal IN3 does not include information on hard arc generation despite the hard arc generation b. Accordingly, the hard arc detection signal OUT3 is generated in response to the hard arc generation b.

When the difference between the generation time of the first soft arc detection signal OUT1 and the generation time of the second soft arc detection signal OUT2 is within the range of the reference slope signal T_slope, the soft arc generation signal S1 is When the second soft arc detection signal OUT2 becomes high, the high signal is high. The soft arc generation signal S1 is low when the first soft arc detection signal OUT1 is low. (low).

Arc generation (c) lasts for less than a certain time (streamer duration Tstm). When the duration of the arc generation c is within the streamer duration Tstm, the soft arc generation signal S1 may be treated as a soft arc. On the other hand, the arc generation (d) may be longer than the streamer duration (Tstm). The arc generation (d) may be determined as a streamer. On the other hand, in order to determine the duration of the arc generation (c), the first soft arc detection signal OUT1, the second soft arc detection signal OUT2, and / or the soft arc generation signal S1 If used, this may yield incorrect results. In detail, the first reference signal REF1 may not be able to maintain a steady state value for the duration of the arc due to the frequency characteristic of the first reference signal generator. Accordingly, the first soft arc detection signal OUT1 corresponding to the arc generation c and d may not substantially indicate the duration of the arc.

In order to determine the arc generation (d) as a streamer, it may further include a change in the current envelope signal Irms and / or the duration of the voltage envelope signal Vrms. Specifically, when the current envelope signal Irms is almost unchanged despite the arc generation d, the arc generation d may be treated as a streamer. In addition, when the value of the voltage envelope signal Vrms is longer than the streamer duration Tstm, it may be determined as a streamer.

When it is determined that the arc generation d is a streamer, an interlock signal INT_LCK for controlling the power supply 3 may be generated. The total arc count signal ARC_CNT may include the frequency of occurrence of the soft arcs (a, c, d) and hard arc (b).

According to a modified embodiment of the present invention, when the arc generation signal S1 or the hard arc detection signal OUT3 is generated, the determination unit 10 may perform the arc generation signal S1 through an interface 8. ) Or the hard arc detection signal OUT3 to the power source 3. The power source 3 may be turned on again after being turned off for a predetermined time by receiving the arc generation signal S1 or the hard arc detection signal OUT3.

8 is a block diagram showing the configuration of a soft arc determiner according to an embodiment of the present invention.

Referring to FIG. 8, the soft arc determiner 60 includes first and second NAND circuits 100 and 106, a counter 102, a comparator 104, and a flip-flop 108.

The first NAND circuit 100 receives a first soft arc detection signal OUT1 and a clock signal CLK, and outputs a NAND operation. The counter 102 calculates the number of pulses of the output signal of the first NAND circuit 100. The comparator 104 compares the reference slope signal T_slope with the output signal of the counter and outputs a high value within a predetermined range. The reference slope signal T_slope is a value set by the controller 34. The flip-flop 108 receives the output signal of the comparator 104 and the second soft arc detection signal OUT2, and soft arcs at the rising edge of the second soft arc detection signal OUT2. The generation signal S1 may be output. The second NAND circuit 106 may receive the first soft arc detection signal OUT1 and the reset signal RST and perform a NAND operation to output the NAND operation. The reset signal RST may be a value set by the controller. The output signal of the second NAND circuit 106 is connected to reset the counter 102 and the flip-flop 108. The counter 102 and the flip-flop 108 may each invert the output signal of the second NAND circuit 106 and use it as a reset signal. The reset signal RST may be set high for a predetermined time. Accordingly, when the first arc detection signal OUT1 becomes low, the counter 102 may be reset and the flip-flop 108 may be reset.

The soft arc determiner 60 may be variously modified to determine the slope and / or width of the voltage envelope signal Vrms.

9 is a block diagram showing a configuration of a processing unit according to another embodiment of the present invention. Description of the same configuration as that described in FIG. 3 is omitted. According to the present embodiment, the determination of the soft arc generation may be determined with the width of the first soft arc detection signal OUT1. When the first soft arc detection signal OUT1 is within a predetermined time range, it may be determined as a soft arc. In addition, the determination of whether the streamer is as described with reference to FIG. 3.

10 to 12 are flowcharts illustrating an arc detection method according to an embodiment of the present invention. The arc sensing method described below may be implemented through the arc sensing apparatus described above with reference to FIGS. 1 to 9.

10 to 12, for the arc detection of the present invention in the RF discharge in which the power supply to the load through the transmission line, by measuring the electrical signal of the current or voltage of the transmission line current signal (SI ') and voltage A signal SV 'is generated (S10). The electrical scene of the voltage and current of the transmission line is measured by means of a voltage meter and an electric meter. The current meter may output a signal in the form of a voltage.

The generating of the arc detection signal (S20) processes the current signal SI 'and the voltage signal SV' to generate the current envelope signal and the voltage envelope signals Irms and Vrms (S21). A driving frequency component is removed from the current signal SI 'and the voltage signal SV' to form the current envelope signal Irms and the voltage envelope signal Vrms. The current envelope signal Irs and the voltage envelope signal Vrms include information on arc generation. The current envelope signal Irs and the voltage envelope signal Vrms may have an RMS value or a maximum value. Filters may be used to remove the drive frequency components. The voltage envelope signal Vrms or the current envelope signal Irms may change according to arc generation. In the voltage envelope signal Vrms, a comparison signal is generated by including information on an arc but removing unnecessary noise components (S23). In addition, the reference signal is generated by removing information on the arc from the voltage envelope signal Vrms (S22). However, there may be an offset between the comparison signal and the reference signal in order to compare the comparison signal with the reference signal. As a result, the arc detection signal OUT is formed by comparing the comparison signal with the reference signal (S25). The arc detection signal OUT may include a first soft arc detection signal OUT1 and a second soft arc detection signal OUT2. Here, the first soft arc detection signal OUT1 and the second soft arc detection signal OUT2 may be due to a difference in offset. The arc detection signal OUT may include a hard arc detection signal OUT3. The hard arc detection signal OUT3 is generated using the current envelope signal Vrms in the same manner as the first soft arc detection signal.

The arc detection signal OUT determines whether it is a soft arc or a hard arc (S30). Whether or not the soft arc is generated is determined using the slope and / or width of the voltage envelope signal Vrms corresponding to the arc generation. On the other hand, the hard arc is determined using the slope and / or width of the current envelope signal (Vrms). For example, when the difference between the occurrence time points of the first soft arc detection signal OUT1 and the second soft arc detection signal OUT2 is used, the slope of the voltage envelope signal Vrms corresponding to the arc generation may be calculated. Can be. If the difference between the generation time point of the first soft arc detection signal OUT1 and the second soft arc detection signal OUT2 is within the range of the reference slope signal T_slope, the soft arc generation signal S1 is generated (S31). . The frequency of occurrence of the soft arc generation signal may be counted and output (S32).

The interlock signal INT_LCK is generated using the soft arc generation signal S1, the change of the current envelope signal Irms, and the duration of the voltage envelope signal Vrms (S33). When a streamer type soft arc occurs, the voltage envelope signal Vrms may decrease from the steady state over the streamer duration Tstm, and the current envelope signal Irms may hardly change in the steady state. Accordingly, when the current envelope signal Irms is hardly changed and the voltage envelope signal Vrms is maintained for more than the streamer duration Tstm, the interlock signal INT_LCK is generated. When the streamer occurs, the power source may be damaged. To prevent this, when the streamer is generated, the power may be controlled by the interlock signal INT_LCK.

1 is a block diagram showing a schematic configuration of an arc detection apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of the processing unit 25 described with reference to FIG. 1.

3 is a block diagram illustrating a schematic configuration of a preliminary processing unit and a determination unit according to an embodiment of the present invention.

Figure 4 is a block diagram showing the configuration of an arc detector according to an embodiment of the present invention.

FIG. 5 shows the voltage signal SV ′, the first and second comparison signals IN1 and IN2, the first and second reference signals REF1 and REF2, and the first soft signal in the soft arc detector according to an exemplary embodiment of the present invention. Graphs illustrating the arc detection signal OUT1 and the second soft arc detection signal OUT2. The x-axis represents time, and the y-axis represents voltage (V).

FIG. 6 illustrates a first comparison signal IN1, first and second reference signals REF1 and REF2, a first soft arc detection signal OUT1, and a second soft arc detection signal according to the arc generation A of FIG. 5. These graphs show (OUT2).

7 is a diagram illustrating first and second comparison signals IN1 and IN2, third comparison signal IN3, first and second reference signals REF1 and REF2, and a third reference in a processor according to an exemplary embodiment of the present invention. The signal REF3, the first and second soft arc detection signals OUT1 and OUT2, the hard arc detection signal OUT3, the soft arc generation signal S1, the total arc count signal ARC_CNT, and the interlock signal INT_LCK. It is a graph.

8 is a block diagram showing the configuration of a soft arc determiner according to an embodiment of the present invention.

9 is a block diagram showing a configuration of a processing unit according to another embodiment of the present invention.

10 to 12 are flowcharts illustrating an arc detection method according to an embodiment of the present invention.

Claims (19)

In an RF discharge in which a power source supplies power to a load through a transmission line, A detector for measuring an electrical signal of a current or voltage of the transmission line; And It includes a processing unit for determining the occurrence of the arc by processing the voltage signal or current signal that is the output signal of the detection unit, And the processing unit processes the voltage signal or the current signal to generate an envelope signal, and determines whether an arc is generated using the envelope signal corresponding to the arc generation at the load. According to claim 1, The processing unit A preprocessor configured to process the voltage signal to generate a soft arc detection signal and / or the envelope signal; And It includes a determination unit for determining the soft arc generation using the slope of the envelope signal, And the envelope signal is a voltage envelope signal obtained by processing the voltage signal. The method of claim 2, The processing unit A digital analog converter which converts an offset signal into an analog signal to generate an analog offset signal and transmits the analog offset signal to the preprocessor; An analog-digital converter for converting the envelope signal of the preliminary processing unit into a digital signal and providing the digital signal to the determination unit; A control unit controlling the determination unit; And Further comprising at least one of an interface for communicating with the determination unit or the control unit and an external power source, host, input / output device, HMI, etc., And the offset signal is provided by any one of the host, the control unit, and the determination unit. The method of claim 2, The preprocessing unit An envelope generator configured to process the voltage signal to generate the voltage envelope signal; A first soft arc detector for generating a first soft arc detection signal; And And a second soft arc detector for generating a second soft arc detection signal. The method of claim 4, wherein The first soft arc detector is Comparing a first comparison signal and a first reference signal to generate the first soft arc detection signal, A first reference signal generator for processing the voltage envelope signal to generate the first reference signal from which arc information is removed; A first comparison signal generator for processing the voltage envelope signal to generate a first comparison signal including information about an arc; And And a first comparator configured to compare the first reference signal and the first comparison signal to generate the first soft arc detection signal. The method of claim 4 The second soft arc detector is Comparing a second comparison signal and a second reference signal to generate the second soft arc detection signal, A second reference signal generator for processing the voltage envelope signal to generate the second reference signal from which information about an arc has been removed; A second comparison signal generator for processing the voltage envelope signal to generate a second comparison signal including information about an arc; And And a second comparator configured to compare the second reference signal and the second comparison signal to generate the second soft arc detection signal. The method of claim 2, The determination unit And a soft arc generation determiner for outputting a soft arc generation signal using a slope of the envelope signal corresponding to arc generation at the load. The method of claim 7, wherein The determination unit And a soft arc counter for calculating the number of the soft arc generation signals. The method of claim 8, The processing unit includes an analog-to-digital converter for converting the envelope signal of the preprocessing unit into a digital signal to output a digital envelope signal, The determiner may include a memory configured to receive the soft arc generation signal as an operation signal and store the digital envelope signal of the analog to digital converter; And And a streamer determiner which receives the soft arc generation signal as an operation signal, determines whether the streamer is changed by using the change of the digital envelope signal and / or the duration of the change, and outputs an interlock signal. Arc detection method. The method of claim 9, The power is controlled using the interlock signal, And the interlock signal is transmitted to the power supply via an interface. According to claim 1, The processing unit A preprocessor configured to process the current signal to generate a hard arc detection signal and / or the envelope signal; And Determination unit for processing the hard arc detection signal, The envelope signal is an arc detection device, characterized in that the current envelope signal processing the current signal. The method of claim 11, wherein The pretreatment unit A current envelope generator configured to process the current signal to generate a current envelope signal; And And a hard arc detector for generating a hard arc detection signal. The method of claim 12, The hard arc detector is Comparing a third comparison signal and the third reference signal to generate the hard arc detection signal, A third reference signal generator for processing the current envelope signal to generate the third reference signal from which arc information is removed; A third comparison signal generator for processing the current envelope signal to generate a third comparison signal including information about an arc; And And a third comparator for comparing the third reference signal with the third comparison signal to generate the hard arc detection signal. The method of claim 13, The determination unit And a hard arc counter for calculating the number of the hard arc detection signals. According to claim 1, The processing unit A preprocessor configured to process the voltage signal or the current signal to generate a soft arc detection signal and / or the envelope signal; And And a determination unit determining a soft arc generation using the width of the envelope signal. In an RF discharge in which a power source supplies power to a load through a transmission line, Sensing current signals of current or voltage of the transmission line to generate current signals and voltage signals; A preprocessing step of processing the voltage signal and the current signal to generate an arc detection signal and an envelope signal; And And determining arc generation using a slope or width of the envelope signal. The method of claim 16, The preliminary processing step Processing the current signal and the voltage signal to generate an envelope signal; Generating an arc detection signal using the envelope signal. The method of claim 17, Generating the arc detection signal is Generating a comparison signal including information on an arc using the envelope signal; Generating a reference signal excluding information on an arc by using the envelope signal; And Comparing the reference signal with the reference signal to form an arc detection signal. The method of claim 16, The determining of the arc generation Processing the arc detection signal to determine an arc generation using a slope of the envelope signal or a width of the envelope signal to generate an arc generation signal; Counting the arc generation signal; Generating an interlock signal using a change and a duration of the arc generation signal and the envelope signal; And And controlling at least one of the at least one power using the interlock signal.

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